2.0 - Configuration and Basic Concepts¶

2.1 - Introduction to Ansible Configuration Files¶

Introduction¶

[defaults]

inventory = /path/to/inventory/file # e.g. /etc/ansible/hosts
log_path = /path/to/log/file # e.g. /var/log/ansible.log

library = /path/to/modules/folder # e.g. /usr/share/my_modules/
roles_path = /path/to/roles/folder # e.g. /etc/ansible/roles
actions_plugins = /path/to/action/plugin # e.g. /user/share/ansible/plugins/action

gathering = implicit # how ansible gathers facts

## SSH Timeout
timeout = 10
forks = 5 # how many hosts can ansible target at any given point

[inventory]

enable_plugins = plugin1, plugin2, plugin3, ...

[privilege_escalation]

[paramiko_connection]

[ssh_connection]

[persistent_connection]

[colors]

Ansible will, unless specified otherwise, refer to this configuration when any playbook is ran on the control machine.
This isn't mandatory, one can define specific configuration files for specific playbooks based on use cases, make a copy of the config file in the playbooks directory(ies), and make the changes accordingly.
Upon execution, any config file in the playbook's directory will take precedence over the default.
If the config file is to be stored away from the playbook directory, add the environment variable $ANSIBLE_CONFIG=/path/to/file prior to any ansible-playbook command.
In terms of precedence, config files specified by $ANSIBLE_CONFIG will take top priority, then any cfg in the playbook's directory, then .ansible.cfg in the user home directory, and finally /etc/ansible/ansible.cfg.
Note: The cfg files outside of the default location do not have to have every single parameter defined, only the ones which you wish to override.
In the event of only one or two variables needing to be overwritten, one could add ANSIBLE_<CONFIG PARAMETER NAME>=value prior to ansible-playbook execution.
This would take top priority, but does not persist command to command.
One could export the variable to persist in the shell.
To persist outright across shells, it's advised to create a new ansible.cfg file in the desired location.
To understand the configurations available and default values, use ansible-config list.
To view the current config file: ansible-config view
To view the current settings and where the settings are set from e.g. environment variables: ansible-config dump

04.1 - Introduction to YAML¶

Introduction¶

All Ansible Playbooks are written in YAML
Text or Configuration files
Analagous to the likes of JSON and XML, YAML is just another way of representing data

Generally, data is presented in key-value pairs i.e.
Key-Value Pair:

key1: value1

Arrays:
- indicates an element of an array

array1:
- key1: value1
- key2: value2

Dictionaries:
All entries in a particular dictionary offset by a set amount of spaces.

dictionary:
  key1: value1
  key2: value2

dictionary2:
  key1: value1

Spacing determines what data is a property of which, any values that are child properties of a particular parent must have the same amount of spaces before definition.
Note:
You may have a need to store different sets of information for a particular "thing".
Dictionary within dictionaries are used for using multiple values of different types
Arrays used for different values of the same types
Use a list of dictionaries for storing the same set of information for multiple entries of similar nature. In the example below, each element in the array is in fact a dictionary.

yaml Fruits: - Banana: calories: value fat: value carbs: value - Grape: calories: value fat: value carbs: value
When to use dictionaries v lists:
Dictionary = Unordered data
List = Ordered

Exercises¶

Given a dictionary with the property property1 and value value1

Add an additional property property2 and value value2.

yaml property1: value1 property2: value2

1.

Given a dictionary with the property name and value apple. Add additional properties to the dictionary.

Key/Property	Value
name	apple
color	red
weight	90g

yaml name: apple color: red weight: 90g

1.

A dictionary employee is given. Add the remaining properties to it using information from the table below.

Key/Property	Value
name	john
gender	male
age	24

yaml employee: name: john gender: male age: 24

Now try adding the address information. Note the address is a dictionary

Key/Property	Value
name	john
gender	male
age	24
address	Key/PropertyValuecityedisonstatenew jerseycountryunited states

yaml employee: name: john gender: male age: 24 address: city: edison state: new jersey country: united states

Given an array of apples. Add a new apple to the list to make it a total of 4.
add two more
add two mangoes to the list

yaml - apple - apple - apple - apple - apple - apple - mango - mango

1.

We would like to add additional details for each item, such as color, weight etc. We have updated the first one for you. Similarly modify the remaining items to match the below data.

Fruit	Color	Weight
apple	red	100g
apple	red	90g
mango	yellow	150g

yaml - name: apple color: red weight: 100g - name: apple color: red weight: 90g - name: mango color: yellow weight: 150g

We would like to record information about multiple employees. Convert the dictionary employee to an array employees

yaml employees: - name: john gender: male age: 24

Add an additional employee to the list using the below information.

Key/Property	Value
name	sarah
gender	female
age	28

yaml employees: - name: john gender: male age: 24 - name: sarah gender: female age: 28

1.

Now try adding the pay information. Remember while address is a dictionary, payslips is an array of month and amount

Key/Property	Value
name	john
gender	male
age	24
address	...
payslips	#monthamount1june14002july24003august3400

yaml employee: name: john gender: male age: 24 address: city: edison state: 'new jersey' country: 'united states' payslips: - month: june amount: 1400 - month: july amount: 2400 - month: august amount: 3400